Television receiver



Nov. 29, 1932. D FAHRNEY 1,889,727

TELEVISION RECEIVER Filed Sept. 3, 1931 I \/E U HMQW ATTEJRHELI:

Patented Nov. 29, 1932 UNITED. STATES PATENT [OF Fl ck; v

came 1). FAHRNEY, or CAMBRIDGE, MASSACHUSETTS rnrnvrsronnncnrvnn iApplication filed September My invention relates to televisionreceiversand has for its basic object the reassembling of unit light va-lues andthe display of picbling and display member in parallel strips or otherorder of units in accordance with the method of scanning or imagedissection employed in transmission of the pictures or images to bereceived and exhibited.

tion and accompanying drawing, which form a partof this specification,but it is to be understood that said drawing is-merely illustrative andis not to be taken as restrictive.

The illustrations in the accompanying drawing show an adaptation of theprinciples of my'invention to be a receiver of drum type,

in which: ,7

Figure 1 represents an elevation of a device partly in sectionand partlydiagrammatical with a section of a picture reassembling and dlsplaymember shown in connection there-- with. g

Figure 2 represents a view from above of the device shown in Figure 1,the same being also partly in sectionand partly in diagram.

Proceeding with a detailed description, 1 in Q Fig. 1 represents insection a rotatable member of drum type here shown operative inahorizontal position and provided in its pe-- ripheral casing with aconvolution of aper- V tures,'one' of which'is indicated by 2 and whichapertures are here arranged in a spiral,

the total number of apertures corresponding with the number of linesemployed intransmission of the picture to be received.

Means are provided for sustaining a "lens 3 which may be of vanysuitable type in line with each aperture, which lenses may be circular,or for the sake of compactness and the The modulated light producinglamp'a is a, 1931. Serial No. 560,891.

utilization of relatively larger ones, they may I otherfa's here shown.

One means sustalmng'the lenses rad1ally,

bedeleted on their sides adjacent to one an- .as shown in the drawing,being'to' produce an aperture in the casing of the drum from the insidelarge enough to ins'ertthe lens witha "flange provided by a reduction ofthe size-of the-aperture in the outer surface of the casing to preventthe lens from passing through, 'successiveenlargements of theaperturefrom the inside being made, where desired, providing sustainingshoulders or collars for additional lenses; means being provided forholding the lensesvimmovably when once properly pla'ced,[but I do notwish to belimited to this method of positioning or sustaining the Otherobjects of my invention will be apparent from the following detaileddescripmay shown mounted directly on thedriving shaft of a motorindicated by 4, in'both figures, which motor may'be of synchronous typeor in place thereofaphonic wheel adaptation or other means now wellknown to those versed in the art may be employed for maintainingsynchronism with the-speeds .employed in transmission. In 'practice theusual framing and operative control features-are provided and means mayalso be provided for shifting the receiver into difierent speeds fortuning in with different transmitting stations that employdifi'erentspeeds in scanning, but it is not deemed necessary to illus-.tratesuch details herein. 7 i 5 in both figures'r'epresents a lamp whichmaybe of the point orc rater type for supplying the modulated lightrepresenting the unitlightvalues of the obj ect'or image .tran'smittedthe lampv inFigQl of the drawing being shown with 'a rectangular lightemitting aperture to cause the light'spot focused onto a screen to alsoberectangular inform while the lamp shown in Fig.- 2 shows a round lightemitting aperture'b'ut I do not wish to beli-mited to any particulartype'of; lamp for the purpose. I

here shown positioned within the rotatable aperture carrying drum 1 withits modulated light open to the path of the rotatory apertures, whichlight may be confined by a condensing element if desired.

In operation, as the drum 1 r'otates, the apertures in turn permit thepassage of llght from the source while the lenses sustained in line witheach aperture and indicated by 3 in both figures of the drawing condenseand focus the light rays 'fromthe lamp 5 and cause horizontal lines oflight to be traced on a member 6 here shown partly in section, whichmember may consist of a plain or reflective screen or maybe oftranslucent nature for viewing thepicture from theside .oppositefrom thelight supply, means. (not shown) being provided for adjustablysupporting the light element and also the picture display member 6. p

, The radial spread of successive beams of light passed by successiveapertures is determined and may be controlled in the adaptation hereshown by the distance between the apertures and accompanying lenscenters and I tions as to prevent more than one spot of light fromshowing on the display member at any one time.

- In operation, with the modulated light functioning, by revolving theapertured member 1, a spot'of light is directed and focused onto thescreen 6 and caused to trace a horizontal line of light thereon, thediffer- I cut apertures functioning one after another in like manner inthe order arranged.-

" 6 curved accordingly in this direction, but

-In the screening process described it is readily apparent that in casea fiat screening member is used the distance from the light source todlfi'erentportions of the scanned surface varies accordingly with theresultthat the lenses if all alike do not maintain an exact focus of thetraveling light spot onto all parts of the surface with detrimentaleffects in sharpness of detail and flaring of the lines transverselytowards the edges of the scanned area. a

To overcome this objectionable lack of uniform focusing on the screen inthe plane of the traveling spots oflight, I show the screen this stillleaves the greater of the two evils uncorrected.

I therefore provide lenses-of different focal lengths corresponding withthe, relative distances between the different lines traced on thepicture display 'mentiberand the light source. V

In practice, where the light units forming the pictures are thrown ontoa screen to be viewed from the same side, it is preferable to positionthe light source 5 on a horizontal plane not higher than that of thelowest aperture of the cycle or series, which accordingly calls for thefunctioning of the lensof shortest focal length employed, in tracing thebottom line, each of the succeeding lenses being of a different andcorrespondingly increased focal length, reaching the maximum with theother extreme lens of the cycle functioning at the top or oppositeextreme of the illuminated area of the screen element, it beingperfectly feasible, however, to scan the picture area by linesprogressing either from the top downward or in the opposite direction,or in any other order by a corresponding adaptation of the elements.

Through adaptations of the devices and methods outlined, the screenedand assembled picturemay be at an elevation making the picture visibleabove the plane of the mechanism and housing, or still higher if,desired.

In this adaptation, the screen member may be adjustably supported as anelement of the device or it may be sustained by separate means or hungon a wall at proper distance.

In an adaptation of the principle and de-.

vice where it is preferable to direct the lines of light and reconstructthe picture for display on a member of translucent nature, to be viewedfrom't-he back, so to speak, the light source 5 may be positioned on aplane equi-.

distant between that of the extreme apertures of the cycle,as shown inFig.1, the lenses increasing in focal length both ways from the basicplane of the light source, although the scanning and re-assembling ofthe picture may take place in successive lines either from top orbottomor in accordance with the order of line scanning employed intransmission of the image or object being received and reassembled forobservation. In the process illustrated, it is obvious to those versedin the art that lenses of condensing type or of different combinationsmay be employed between the modulated light source and the path of thelens studded apertures de: scribed, or between the path of the aperturesand thepicture display member, but I have not deemed it necessary'toshow them in the drawing for the reason that it would not be practicableto illustrate all of the various types and combinations of lensesfeasible for the purpose. Y

It is also be understood that instead of a single lens sustained in linewith each aperture of the rotatable carrier member, I may employ .aplurality of lenses in connection with each aperture so selected andpositioned relatively as to perform the, functions outlined herein.

Having thus described illustrative embodiments of my; invention without,however,

limiting the same thereto, what Iclaim and desire to secure by LettersPatent 1s:

1. In a television receiver a rotatable member of drum type provided inits peripheral scanning employed in transmission with means sustainingunlike lenses of different focal lengths in line with each aperture fordirecting and focusing the light from a modulated light source onto apicture assembling and display member in parallel lines, the picturedisplay member being curved one way in the direction of the saidrotatable drum.

3. In a television receiver a horizontally rotatable member of drum typeprovided in its peripheral section with a convolution of aperturesarranged in accordance with the order of line scanning employed intransmission with means sustaining unlike lenses in line with'eachaperture, the lenses increasing in focal length in accordance with theincreased distance between a modulated light source and parallel linesdirected onto a horizontally curved picture assembling and displaymember. j

4. In a television receiver a horizontally rotatable member of drum typeprovided in its peripheral casing with a convolution of aperturesarranged in accordance with the order of line scanning employed intransmission, means sustaining a lens in line with each of saidapertures, a modulated light source positioned on one side of the pathof said apertures and a horizontally curved picture assembling anddisplay member on the other side, the said lenses being unlike and ofdifferent focal lengths in accordance with the relative distance betweenthe said light source and the different horizontal lines of light tracedand focused on the said picture display member by each lens in the orderar ranged.

5. In a television receiver, in combination, a rotatable member of drumtype provided in its peripheral region with a convolution of aperturesarranged in the order of line scanning employed in transmission, meanssustaining unlike lenses of different focal lengths in line with each ofsaid apertures, a modulated light source directed onto one side of theapertures as they pass a given area, a one way curved picture assemblingand display member positioned to receive the modulated light incondensed form in parallel lines as focused thereon by the said lensesin succession, the lenses being of different focal lengths in accordancewith the distance between each one and the line focused by it v andtraced on the said display member.

6. In a television receiver, a horizontally rotatable member of drumtype provided in ranged in accordancewith'the order of line scanningemployed in transm1ss1on,.means sustaining unlike lenses in line witheach of 7 said apertures, a horizontally curved picture display memberof translucent nature positioned on one side of the path of saidapertur'es and a modulated light directed onto them from the other side,the lenses being of different focal length in accordance with thedistance from the llght source to lines focused by each lens in turnonto the said picture display member and traced thereon in horizontallines in the order arranged.

7. In a television receiver, a rotatable member of drum type provided inits peripheral section with apertures arranged in accordance with theorder of line scanning employed in transmission, means sustaining unlikelenses in line with each of said apertures,

a picture assembly and display member of translucent nature positioned'to be traced by parallel lines of light focused thereon by each of saidlenses in single order from a modulated light source, the said lensesbeing of different focal lengths in accordance with the distance betweenthe said light source and the respective lines traced on the saiddisplay member. a

8. In a television receiver a rotatable member provided in itsperipheral section with a convolution of apertures arranged in the orderof line scanning employed in transmission with means sustaining in linewith each aperture unlike lenses of different focal lengths, the lensesbeing deleted on their sides adjacent to one another.

CALLO D. FAHRNEY.

in its peripheral section with apertures ar-

